The present invention relates to an equalizer for equalizing both the amplitude distortion and the delay distortion of a communication transmission channel.
A prior type of manually adjustable equalizer is provided with a plurality of circuits, each having a convex curved characteristic called a "bump". Both the amplitude characteristic and the delay characteristic, and the combination of these circuits, provided the desired characteristics.
However, prior techniques have the disadvantage that a considerable amount of time and labor is required for adjustment, so as to obtain the desired combined characteristics. This is to say, in FIG. 1, supposing that the desired characteristics 24 is combined by the characteristics 21, 22 and 23, the adjustment of the peak value 22 of the component circuit readily causes an interference with another values of the curves 21 and 23 in the frequency range under the control of the adjacent component circuits.